Apparatus for heating metallic billets, bars or the like by direct passage of current



Dec. 10, 1963 E. BREUER ETAL 3,114,034

APPARATUS FOR HEATING METALLIC BILLETS, BARS OR THE LIKE BY DIRECT PASSAGE OF CURRENT Filed Aug. 10, 1961 2 Sheets-Sheet 1 [fr/0,1; Breuer Werner KLeLho n INVENTORS E. BREUER ETAL Dec. 10, 1963 3,114,034

APPARATUS FOR HEATING METALLIC BILLETS, BARS OR THE LIKE BY DIRECT PASSAGE OF CURRENT Filed Aug. 10, 1961 2 Sheets-Sheet 2 Erich Breuer Werner KieLhorn INVENTORS United States Patent APPARATUS FQR HEATHNG METALLM BILLETS, BARS OR THE LIKE BY DIRECT PASSAGE 6F CU NT Erich Breuer, Dortmund, and Werner Kielhorn, Essen- Steele, Germany, assignors to Brown, Boyer-i dz Cie Aktiengesellschait, Mannheim, Germany, a joint-stock company Filed Aug. 10, 1961, Ser. No. 130,6tl7 Claims priority, application Germany Aug. 18, 1960 Claims. (Cl. 219-456) The heating of rolling billets, bars, or similar elongated metallic materials, in particular of steel, by passing an electric current therethrough for processing is known. In known devices serving this purpose, the workpieces are introduced into the device either from the side or from below crosswise to their longitudinal direction. Alter introduction, suitable contact devices-in the following called electrodes-are pressed onto the ends of the workpieces. In these arangements the electrodes must be moved to one side for introduction and removal of the workpieces. Also, such a device requires relatively much space in lateral direction, so that it is difficult to set up side by side several such devices for the heating of billets to be treated in the same rolling mill.

-Also billet heating devices of the kind mentioned are known in which, to avoid the last-named disadvantage, the billets are run in and out in their longitudinal direction. In a known embodiment of this kind, the billets, after having been brought to the proper place on a roller bed, are lifted oil the roller bed by means of a special lifting device engaging from below and are pressed against electrodes fixed thereabove. A disadvantage here is the special lifting device, which in particular for devices for heating long billets must contain additional supports distributed along the billet to prevent the billet from sagging during heating. Such a lifting device involves not only an undesired complication of the installation; it also makes it impossible to arrange the heavy current transformer be longing to the installation below the billet to be heated as would be desirable to save space and to obtain shortheavy-current leads to the electrodes.

Also it appeared that the current leads to the workpiece through electrodes laterally pressed against the ends thereof do not insure a satisfactory current transmission to the workpiece. For this reason, electrodes have been provided which can be pressed against the front ends of the workpiece and which conduct heating current to the workpiece either alone or jointly with laterally applicable electrodes. Such irontally applicable electrodes have, however, not yet been provided in heating installation into which the billets are introduced in their longitudinal direction.

The invention relates to a device for heating metallic bars, billets, or the like by direct passages of current, into which the workpieces are introduced in their longitudinal direction through a roller bed or similar con veying device and discharged therefrom.

To avoid the disadvantages hitherto connected with such devices and at the same time to utilize the advantages of a front-end admission, the-device according to the invention is to designed that the workpieces are intro duced, heated, and discharged Without a transverse displacement, and that the electrodes or their holding devices are so designed that after detachment of the electrodes tfirom the workpiece they can be moved out of the conveyor track. By transverse displacement must be understood a movement of the workpieces directed crosswise to the direction of conveyance to the sides or upward or downward.

For further perfection of the device there may be provided, addition to the f-rontally applicable electrodes, other electrodes which are applicable to the workpiece ends from the sides.

in the accompanying drawing, an example for construction of the invention is illustrated.

FIG. 1 shows a side view of the device with a section through the foundation.

FIG. 2 represents a transverse section through the device along line 2-2 of FIGURE 1.

The material to be heated, eg. a long rolling billet is designated at 1. A step-down transformer 2, which produces the required heavy current at low voltage, is arranged in the lower part of the device. Tubular conductors 3, possibly Water-cooled, constitute together with flexible conductors 1-3, which for the sake of clarity are shown in part broken away, the current connection to the electrodes or electrode supports 4- and 5. The arrangement of these conductors 3 is made such that they extend substantially parallel to the introduced billet and at equal distance therefrom, as is evident from FIG- URE 2.

In this way a uniform current distribution in the conductors is achieved at small inductivity of the current loops.

The electrodes are guided in frames 6 and 7, of which at least the latter is movable on rails 8 by means of rolls 9 to compensate the thermal elongation of the billet. For the longitudinal displacement or frame '7 there may serve devices not shown, such as screw spindles, racks, or hydraulic pressure cylinders. By the movaoility of frame 7 the device can be adapted to different lengths of the billets, it being possible also to shift the connections of the flexible conductors 13 to the fixed tubular conductors 3. The electrodes or their holding devices 5 are displaceable obliquely downward on fixed rails 15, for example,

by means of a swallows tail track. To carry out these displacements there serve laterally arranged hydraulic drives it). By a dis-placement of the electrodes obliquely downward, the conveyance of the billet 1 in longitudinal direction becomes possible without a movement of the billet upward or in lateral direction; by an upward movement of the electrodes 5 these are simultaneously brought to the end faces of the billet and pressed against them. Also, there may be provided the possibility of a longitudinal displacement of the actual contact bodies 16 within the holding device 5 of the electrodes.

The laterally applicable electrodes 4' may be movable in known manner by devices not shown, for example, hydraulic pressure cylinders.

For the longitudinal movement of billet 1 before and fiterqthe heating process there serves a roller bed which is indicated only in FIGURE 1 by a cross-section representation of the rolls 11. The rolls ll must be electrically insulated. This can be done, for example, in that the shells of the rolls are supported against their shatts by ceramic material. The device is arranged in a pit 14 in such a way that the movement of the rolling billets and the heating thereof occurs in a plane which lies but little above the mill floor.

The invention is not (limited to the example shown, but can be modified in various ways. For example, instead of the device for the movement of the electrodes 5 in oblique direction there may be provided a laterally pivotab-le electrode support, in which the electrodes are displaceable in axial direction, for example, by pressure cylinders. The arrangement of the current leads to the electrodes may be selected dilferently from that shown in the example. Nor is it absolutely necessary that the transformer 2 must be arranged below the billet and the roller bed rolls 11.

Depending on local conditions and the space available, an arrangement of the transformer next to the roller bed, for example, may be advantageous. The hydraulic drives provided in the example may be replaced by pneumatic drives or by motor-drives devices.

The device according to the invention may he so arranged that the workpieces are moved on in tle same direction after heating in which they were introduced, or that they are discharged from the device in opposite direction.

We claim:

1. Apparatus for electrically heating an elongated electrically conductive workpiece such as a bii et, bar or the like by passing an electric current longitudinally therethrough comprising an elongated bed establishing a longitudinal axis along which said workpiece is movable longitudinally of itself to a heating position on said axis, electrode means oooperable with opposite end portions of said workpiece, and means mounting said electrode means for movement towards and away from said axis in a direction generally transverse thereto so as to engage and be disengaged from said end portions of said workpiece thereby enabling said electrodes to he shifted into and out of the path of movement of said workpiece longitudinally of itself along said axis into and out of said heating position.

2. Apparatus as defined in claim 1 for electrically heating an elongated workpiece wherein said electrode means are mounted for movement along an axis perpendicular to said longitudinal axis so as to effect lateral engagement with the end portions of said workpiece.

3. Apparatus as defined in claim 1 for electrically heating an elongated workpiece wherein said electrode means are mounted for movement along an axis oblique to said longitudinal axis so as to effect engagement with the end faces of said workpiece.

4. Apparatus as defined in claim 1 for electrically heating elongated workpiece wherein certain electrodes of said electrode means are mounted for movement along an axis perpendicular to said longitudinal axis so as to effect lateral engagement with the end portions of said workpiece and other electrodes are mounted for movement along an axis oblique in said longitudinal axis so as to effect engagement with the end faces of said workpiece.

5. Apparatus as defined in claim 1 for electrically heating an elongated workpiece wherein said electrode means are mounted for pivotal movement towards and away from said longitudinal axis so as to effect engagement with the end faces of said workpiece.

Johnson 'et all. Apr. 10, 1928 Stich Feb. 23, 1960 

1. APPARATUS FOR ELECTRICALLY HEATING AN ELONGATED ELECTRICALLY CONDUCTIVE WORKPIECE SUCH AS A BILLET, BAR OR THE LIKE BY PASSING AN ELECTRIC CURRENT LONGITUDINALLY THERETHROUGH COMPRISING AN ELONGATED BED ESTABLISHING A LONGITUDINAL AXIS ALONG WHICH SAID WORKPIECE IS MOVABLE LONGITUDINALLY OF ITSELF TO A HEATING POSITION ON SAID AXIS, ELECTRODE MEANS COOPERABLE WITH OPPOSITE END PORTIONS OF SAID WORKPIECE, AND MEANS MOUNTING SAID ELECTRODE MEANS FOR MOVEMENT TOWARDS AND AWAY FROM SAID AXIS IN A DIRECTION GENERALLY TRANSVERSE THERETO SO AS TO ENGAGE AND BE DISENGAGED FROM SAID END PORTIONS OF SAID WORKPIECE THEREBY ENABLING SAID ELECTRODES TO BE SHIFTED INTO AND OUT OF THE PATH OF MOVEMENT OF SAID WORKPIECE LONGITUDINALLY OF ITSELF ALONG SAID AXIS INTO AND OUT OF SAID HEATING POSITION. 